This invention relates to a female terminal comprising an electric contact portion of a cylindrical shape and an elastic contact piece formed in the electric contact portion.
For example, a conventional female terminal comprises an electric contact portion of a cylindrical shape having a forward opening for insertion of a male terminal, an elastic contact piece extending from the opening inwardly of the electric contact portion, and a protruding portion formed on an inner wall of the electric contact portion for restricting a degree of deflection of the elastic contact piece. Rearwardly of the electric contact portion, an insulation crimping portion and a conductor crimping portion for connecting a wire and a conductor, respectively, are formed.
Before the male terminal is inserted into the electric contact portion, the elastic contact piece is apart from the protruding portion. When the male terminal is inserted into the electric contact portion, the elastic contact piece is deflected to approach an outer periphery of the protruding portion. In this state, a little gap is left between the elastic contact piece and the outer periphery of the protruding portion. The elastic contact piece exerts its elastic force to press the male terminal against the inner wall of the electric contact portion. If the elastic contact piece is excessively deflected, the elastic contact piece is brought into contact with the outer periphery of the protruding portion. Thus, excessive displacement is prevented.
Instead of the male terminal, a probe of a tester for a continuity test of the female terminal or an extractor jig for extracting the female terminal from a terminal receptacle of a connector may be inserted into the electric contact portion of the female terminal. If the probe of the tester or the extractor Jig is brought into contact with the elastic contact piece in the vicinity of a bending portion thereof, the elastic contact piece is deformed due to presence of a gap between the elastic contact piece and the protruding portion. In this event, the elastic contact piece is plastically deformed to lose its elasticity. This phenomenon is called fatigue.
When the elastic contact piece loses its elasticity, it is impossible to press the male terminal against the electric contact portion and to hold the male terminal. In this event, a gap is formed between the electric contact portion and the male terminal. This results in a continuity failure.